This invention relates to an automatic tracking control method in a video tape recorder and particularly although not exclusively to a method for continually sustaining an optimized tracking level by monitoring the tracking levels.
In FIG. 1, a block diagram of a general tracking control device in a video tape recorder system is schematically illustrated, wherein a program contained in a system controller 6 generates tracking data TRDT to a servo 7 and then, the servo 7 provides a deck 1 with a capstan control signal CAP-CTL in accordance with the tracking data TRDT, to control a rotational speed of a capstan. Then, a head in the deck 1 picks up an instataneous tracking level indicative of a current tracking state according to the rotational speed of the capstan and provides the instantaneous tracking level to the system controller 6, to sustain an optimized tracking level by comparing instantaneous tracking levels.
FIGS. 2A to 2D, disclose a conventional automatic tracking method performed by the videotape recorder system of FIG. 1 as in Korean Patent application No. 89-19419. According to the conventional method, the system controller 6 having an analog-to-digital converter therein executes the automatic tracking as shown in FIGS. 2A to 2D. However, when such an automatic tracking method is employed, in some occasions the system controller 6 may misrecognize variation valves of the instantaneous tracking levels picked up by the head and/or may result in a mal-operation because the automatic tracking operation depends simply on a comparison of the instantaneous tracking levels by means of the system controller 6. Therefore, occasionally, a noisy video signal may be misrecognized for a nose-free video signal particularly when a worn-out video tape is used, and thus the optomized tracking level may be miscalculated, thereby resulting in deteriorated automatic tracking.